Color developing process utilizing pyridinium salts



United States Patent .0

US. Cl. 96-55 Claims ABSTRACT OF THE DISCLOSURE An improved color developer is prepared by combining a p-phenylene diamine with (A) a cationic compound selected from the group consisting of a cationic compound having a pyridinium group represented by the general formula and a cationic compound having the pyridinium group represented by the general formula:

wherein A represents an atomic group consisting of a methylene chain and a group selected from O, --NHCO-, and OCO; B represents a member selected from a saturated alkyl group, an unsaturated alkyl group and a hydrogen atom; R and R represent a member selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms; X- represents a member selected from 2C1, 2Br-, SO and 2ClO Y- represents a member selected from Cl", Br, and C 1 and (B) at least one member selected from a group consisting of N-methyl-p-aminophenol, o,p-diamino phenol, N-benzyl-p-aminophenol and p-aminophenol. Use of these compounds in the color developing process results in a film having reduced color contamination, increased color density, and improved silver bleaching.

The present invention relates generally to a color developing process for a silver halide color photographic element and more particularly to a color developing process using a cationic compound of a pyridinium salt type and p-aminophenol or its derivatives thereof to promote the color developing, reducing the deficiency in silver bleaching and color contamination while improving picture quality.

Since a conventional color developer containing as a color developing agent p-phenylencdiamine or its derivatives is low in developing po'wer compared with that of a general black and white developer, the pH value of the processing solution has been raised or the developing procedure has been conducted for a very long period of time. Accordingly, there have hitherto been employed color developing accelerators, but the use of such conventional color developing accelerators frequently causes fogging at unexposed areas resulting in contaminating the picture or images. Further, if the developing time is shortened for preventing the formation of fog, no increase in the color density of the image portions is observed and hence the color developing processing cannot be conducted effectively.

In particular, in a color developing process using a 3,520,689 Patented July 14, 1970 color developer containing couplers therein, the use of accelerators frequently causes undesirable color fogging or color contamination.

Further, the presence of the developing accelerator in a bleaching process for developed silver after the color development frequently reduce the oxidation speed of silver, that is, causes the phenomenon of co-called insuflicient silver bleaching.

Thus, there are presently very few color development accelerators having excellent properties in the above mentioned points.

Accordingly, an object of the present invention is to accelerate the color developing speed and increase the color density.

Another object of the present invention is to improve the silver-bleaching in color photographic processing.

Still a further object of the present invention is to reduce or prevent the contamination or color contamination in color photography.

It has been found that by using a color developer containing p-phenylenediamine or its derivatives added with a pyridinium type cationic compound and p-aminophenol or its derivatives, the color developing speed can be remarkably increased as Well as the silver bleaching improved and hence contamination or color contamination can be reduced to improve the quality of photographic pictures.

It has been known that the use of pyridinium-type cationic compounds alone accelerate developing speed, but it gives at the same time undesirable results in contamination or color contamination. Further, if some kinds of couplers are present at color development, the use of such a developing accelerator will cause insufficient silver bleaching. However, if the developing accelerator is used together with p-aminophenol or its derivatives thereof in color development, the developing speed is accelerated more effectively as compared with the case of using the developing accelerator alone as well as the abovementioned various faults are reduced.

The pyridinium-type cationic compounds to be used in the present invention may be represented by the following general formulas:

M- kx L X- and pear and if it is too small, the effect of the addition there of will be weak. Therefore, the amount of 0.03 g./l. to

0.5 g./l. is preferable.

The p-aminophenol derivatives used in the present invention are N-methylaminophenol sulfate metol), o,pdiaminophenol hydrochloride (amidol), and N-benzyl-paminophenol. Although the effect may be slightly less than those of the above-mentioned aminophenol derivatives, p-arninophenol may be also used in this invention. In this respect, it must be understood that the use of p-aminophenol or its derivatives among black and white developing agents is important in this invention since the use of other black and white developing agents together with the abovementioned developing accelerators increases, on the contrary, the contamination or color contamination. Further, if the above-mentioned p-aminophenol or its derivatives are added alone in a color developer, a black and white development occurs together with a color development, which results in the reduction of color density and only if the amount thereof is properly selected some extent of the increase in color density is observed in a limited range of exposure and developing time. However, if the abovementioned pyridinium salt compounds are present together with the p-aminophenol derivative or p-aminophenol in a color developer, the color density can be remarkably increased without increasing color fog.

A suitable amount of p-aminophenol or its derivatives thereof to be added in the developer is 0.1 to 1 g./l. The amount may be less or higher than the range but if the amount is less than 0.1 g./l. the effect of the addition thereof becomes insufficient and if higher than 1 -g./l. the color density tends to be reduced on the contrary. Two or more kinds of the above-mentioned p-aminophenol and its derivatives thereof may be used in this invention.

Thus, by using the above-mentioned two compounds according to the present invention, said two compounds being impracticable individually owing to their drawbacks, the faults of the two compounds are compensated by each other to make possible the practical use thereof as well as an unexpected remarkable development accelerating effect from the interaction of them.

The present invention may be generally applied to color photographic materials using a color developer containing p-phenylenediamine or its derivatives thereof, such as color negative films, photographic color papers, photographic color reversal films and the like. In particular, the most effective results of this invention can be obtained in the case of conducting this invention about a yellow color developer for photographic color reversal film having technical difiiculties in silver bleaching and color contamination.

The following examples illustrate but do not limit the present invention:

EXAMPLE 1 A test sample which had been prepared by applying a blue-sensitive gelatino silver bromo-iodide emulsion to a cellulose acetate film was exposed by means of a sensitometer and subjected to the following processings:

First development-3 min. at 27 C.

Water rinsing4 min.

Reversal exposure (tungsten lamp)-20O CMS Color development-5 min.

Water rinsing-- 4 min.

Bleaching-2 min.

Water rinsing1 min.

Fixing-2 min.

Water rinsing2 min.

The compositions of the processing baths were as follows:

First developer:

N-Methyl-p-aminophenol sulfate-2.0 g. Sodium sulfite90.0 g. Hydroquinone8.0 g.

Sodium carbonate (monohydrate)52.5 g. Potassium bromide-5 .0 g.

Potassium thiocyanate1.0 g.

Water to make 1 liter.

Color developer:

Sodium sulfite--5.* g. p-Amino-N,N-diethylaniline sulfite2.5 g. Potassium bromide1.0 g. Potassium iodide (0.1% aq. soln.) ml. 1-w-benzoyl-4- p-toluene sulfonamido) acetanilide-1.2 g.

Sodium hydroxideg. Water to make 1 liter.

Bleaching solution Potassium ferricyanide100 g. Potassium bromide-10 g. Borax-2 g. Boric acid-l g. Water to make 1 liter.

Fixing solution Sodium thiosulfate--l50 g. Sodium sulfitel0 g. Water to make 1 liter.

The color density and the silver-bleaching elfect were measured in this processing as about the same as when using the pyridinium compounds, the p-aminophenol derivatives or both, the results of which are shown in Table 1. The color density is shown by the value by measuring the maximum density range of thus processed film using a blue filter light and the silver bleaching effect is shown by the value of the blackened density (D by the remaining silver measured by using a red filter light divided by the color density value (D obtained from measuring by using a blue filter light.

TABLE 1 Compound added in color developer Compound A Benzylamino- Color density Silver bleaching (g./l.) phenol (g./l.) D B max. efiect D /D From the table, it is clear that a yellow color image having high color density and high transparency was obtained by using Compound (A) and benzylaminophenol together as comparedwith the cases of using Compound (A) or benzylaminophenol individually.

EXAMPLE 2 To a cellulose acetate film were applied a red-sensitive gelatino silver bromo-iodide emulsion, a green-sensitive gelatino silverbromo-iodide emulsion, a yellow filter layer composed of colloidal silver for absorbing blue light, and a blue-sensitive silver bromo-iodide emulsion in the order to provide a multilayer color photographic film, which was exposed using a sensitometer and subjected to the following processings:

First development-4 min., at 27 C. Water rinsing--4 min.

Reversal red exposure-100 CMS Cyan color development-5 min. Water rinsing 2 min.

Reversal blue exposure-200 CMS Yellow color development-5 min. Second black and white development--2 min. Water rinsing-2 min.

Reversal white exposure-2000 CMS Magenta color development-5 min. Water rinsing-4 min.

Bleaching-2 min.

Water rinsing-1 min.

Fixing-2 min. Water rinsing-2 min.

The compositions of the first developer and the second black and white developer were the same as the composition of the first developer in Example 1. Other compositions of the processing solutions were as follows:

Cyan color developer:

Sodium sulfite5.0 g. 4-arnino-3-methyl-N.N-diethylaniline hydrochloridel.5 g.

Sodium carbonate (mono-hydrate)-15.0 g. Potassium bromide1.0 g. Potassium iodide (0.1% aq. soln.)-2 ml. 1,S-dihydroxy-Z,6-dibromonaphthalenel.2 g. Sodium hydroxide-2.0 g. Water to make 1 liter.

The composition of the yellow developer was same as that of the color developer in Example 1.

Magenta color developer:

4-amino-3-methyl-N,N-diethylaniline hydrochloride-2.0 g.

Potassium bromide-0.2 g.

1-phenyl-3-(m-nitrobenzoylamino) -5-pyraz0lone-- Sodium hydroxide2.5 g.

n-Butylamine5 ml.

Water to make 1 liter.

The compositions of the bleaching solution and the fixing solution were the same as those in Example 1.

The effect of the addition of the compounds of this invention to the yellow color developer in the above processings is shown in Table 2. In the table, the color density (D )was measured by a blue filter light. The silver bleaching was measured about samples exposed to yellow patch. The color contamination (1) shows the ratio of the color density (D obtained by measuring with green filter light a sample exposed to yellow patch to the color density (D obtained by measuring it with blue filter light, that is, the ratio of unnecessary magenta color components in the yellow image and the color contamination (2) shows the ratio of the color density (D obtained by measuring with blue filter light a sample exposed to magenta patch to the color density (D- obtained by measuring it with green filter light, that is, the ratio of unnecessary yellow components in the magenta image.

TABLE 2 Silver Color con Color eon- Addltion compounds Color bleaching tarninatarninaensity effect tion (1) tion (2) Compound A Metol (D (DB/D a) R/D a) B/ o) O 3. 0 0. l3 0. 83 0. 35 0 3. 2 0. 15 0. 60 0. 36 0. 2 3. 15 0. 08 0. 44 0. 32 0. l5 3. 25 0. 10 0. 52 0. 32 0. 2 3. 65 0. 08 0. 42 0. 32 0. 3 3. 5 0. 06 0. 37 0. 32

EXAMPLE 3 By repeating the procedure in Example 2 using a standard composition as the yellow color developer while added the compounds of this invention in the cyan color developer, the results shown in Table 3 were obtained.

7 necessary yellow components in the cyan color patch and the color contamination (2) shows unnecessary cyan color components inthe yellow patch.

EXAMPLE 4 A gelatino silver bromo-iodide emulsion containing a yellow coupler was applied to a cellulose acetate film to provide a test sample, which was exposed by means of a NSG sensitorneter and then subjected to the following processings:

Color development-S min, at 24 C. Water rinsing-30 sec.

First fixing-4 min.

Water rinsing-5 min.

Bleaching-4 min.

Water rinsing-5 min.

Second fixing4 min.

Water rinsing5 min.

The compositions of the processing solutions were as follows:

Fixing solution: (first) Sodium sulfiteg. Sodium thiosulfate-ISO g. Acetic acid (28% )-48 ml. Boric acid-7 g. Potassium alum15 g. Water to make 1 liter.

Bleaching solution:

Potassium bromideg. Potassium dichromate5 g. Potassium alum-40 g. Sodium acetate--8 g. Acetic acid57 ml. Water to make 1 liter.

Fixing solution (second):

Sodium thiosulfate150 g. Sodium sulfite--15 g. Potassium alum-15 g. Water to make 1 liter.

The results of adding the compounds of this invention in the color developer in the above processings are shown in Table 4.

TABLE 4 Silver Addition Compound Color bleaching density Relative effect Compound B Metol (D sensitivity (D /D Color fog In the table, the relative sensitivity was shown by the relative value of the logarithmic exposure amount at the point where the density reaches fog +0.2.

We claim:

1. In a color developing process for color photographic silver halide materials using a color developer containing a member selected from the group consisting of p-phenylenediamine and the derivatives thereof, the improvement which comprises using said color developer having added therein -(A) a member selected from the group consisting of a'cationic compound having the pyridinium group represented by the general formula and a cationic compound having the pyridinium group represented by the general formula wherein A represents an atomic group consisting of a methylene chain and a group selected from O--, NHCO-, and- OCO-; B represents a member selected from a saturated alkyl group, an unsaturted alkyl group and a hydrogen atom; R and R represent a member selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms; X- represents a member selected from 2Cl*, 2Br, 80.;- and 200;; and Y- represents a member selected from Ch, Br" and 010 and (B) at least one member selected from N-methyl-p-aminophenol, o,p-diaminophenol, N-benzyl p aminophenol and paminophenol, o,p.-diaminophenol,. N-lbenxyl-p-aminophee nol and p-aminophenol.

2. The color developing process as in claim 1, wherein the amount of said component (B) to the color developer is 0.1-1 g./liter.

3. The color developing process as in claim 1, wherein the amount of said component (A) to the color developer is 0.03( ).5 g./liter.

4. The color developing process as in claim 1, wherein said color developer containing said component (A) and said component (B) is a color developer with or without couplers for processing color photographic elements.

5. The color developing process as in claim 4, wherein said color photographic element is a photographic reversal color film to be processed in a coupler containing developer.

I References Cited UNITED STATES PATENTS 2,648,604 8/1953 Welliver etal. ,96-66.3' 3,062,645 11/1962 Carroll 96-55 3,300,305 1/196-7 Pesch et al. -9622 J. TRAVIS BROWN, Primary Examiner US. Cl. XJR. 

